Move clipboard history controller observer to ash/public/cpp

This change is in preparation of multipaste related VK API changes,
where the ChromeVirtualKeyboardDelegate will need to be a
ClipboardHistoryControllerObserver. This will allow the VK to observe
clipboard history changes.

Bug: 1099318
Change-Id: I5535d45255b137219cf76b76f6d94c9bfb5ca9e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2573636Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Matthew Mourgos <mmourgos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833831}

ash/clipboard/clipboard_history_controller_impl.cc

@@ -202,11 +202,13 @@ ClipboardHistoryControllerImpl::~ClipboardHistoryControllerImpl() {
   clipboard_history_->RemoveObserver(this);
 }
 
-void ClipboardHistoryControllerImpl::AddObserver(Observer* observer) const {
+void ClipboardHistoryControllerImpl::AddObserver(
+    ClipboardHistoryController::Observer* observer) const {
   observers_.AddObserver(observer);
 }
 
-void ClipboardHistoryControllerImpl::RemoveObserver(Observer* observer) const {
+void ClipboardHistoryControllerImpl::RemoveObserver(
+    ClipboardHistoryController::Observer* observer) const {
   observers_.RemoveObserver(observer);
 }
 

ash/clipboard/clipboard_history_controller_impl.h

@@ -37,14 +37,6 @@ class ASH_EXPORT ClipboardHistoryControllerImpl
     : public ClipboardHistoryController,
       public ClipboardHistory::Observer {
  public:
-  class Observer : public base::CheckedObserver {
-   public:
-    // Called when the clipboard history menu is shown.
-    virtual void OnClipboardHistoryMenuShown() = 0;
-    // Called when the user pastes from the clipboard history menu.
-    virtual void OnClipboardHistoryPasted() = 0;
-  };
-
   ClipboardHistoryControllerImpl();
   ClipboardHistoryControllerImpl(const ClipboardHistoryControllerImpl&) =
       delete;
@@ -52,8 +44,10 @@ class ASH_EXPORT ClipboardHistoryControllerImpl
       const ClipboardHistoryControllerImpl&) = delete;
   ~ClipboardHistoryControllerImpl() override;
 
-  void AddObserver(Observer* observer) const;
-  void RemoveObserver(Observer* observer) const;
+  void AddObserver(
+      ClipboardHistoryController::Observer* observer) const override;
+  void RemoveObserver(
+      ClipboardHistoryController::Observer* observer) const override;
 
   // Returns if the contextual menu is currently showing.
   bool IsMenuShowing() const;
@@ -123,7 +117,7 @@ class ASH_EXPORT ClipboardHistoryControllerImpl
 
   // Mutable to allow adding/removing from |observers_| through a const
   // ClipboardHistoryControllerImpl.
-  mutable base::ObserverList<Observer> observers_;
+  mutable base::ObserverList<ClipboardHistoryController::Observer> observers_;
 
   // The menu being shown.
   std::unique_ptr<ClipboardHistoryMenuModelAdapter> context_menu_;

ash/clipboard/clipboard_nudge_controller.h

@@ -8,6 +8,7 @@
 #include "ash/ash_export.h"
 #include "ash/clipboard/clipboard_history.h"
 #include "ash/clipboard/clipboard_history_controller_impl.h"
+#include "ash/public/cpp/clipboard_history_controller.h"
 #include "ash/public/cpp/session/session_observer.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/clock.h"
@@ -36,7 +37,7 @@ class ASH_EXPORT ClipboardNudgeController
     : public ClipboardHistory::Observer,
       public ui::ClipboardObserver,
       public SessionObserver,
-      public ClipboardHistoryControllerImpl::Observer {
+      public ClipboardHistoryController::Observer {
  public:
   ClipboardNudgeController(
       ClipboardHistory* clipboard_history,

ash/public/cpp/clipboard_history_controller.h

@@ -8,6 +8,7 @@
 #include <memory>
 
 #include "ash/public/cpp/ash_public_export.h"
+#include "base/observer_list_types.h"
 #include "ui/base/ui_base_types.h"
 
 namespace gfx {
@@ -26,9 +27,20 @@ class ScopedClipboardHistoryPause;
 // clipboard history menu.
 class ASH_PUBLIC_EXPORT ClipboardHistoryController {
  public:
+  class Observer : public base::CheckedObserver {
+   public:
+    // Called when the clipboard history menu is shown.
+    virtual void OnClipboardHistoryMenuShown() {}
+    // Called when the user pastes from the clipboard history menu.
+    virtual void OnClipboardHistoryPasted() {}
+  };
+
   // Returns the singleton instance.
   static ClipboardHistoryController* Get();
 
+  virtual void AddObserver(Observer* observer) const = 0;
+  virtual void RemoveObserver(Observer* observer) const = 0;
+
   // Returns whether the clipboard history menu is able to show.
   virtual bool CanShowMenu() const = 0;